Air gun

ABSTRACT

An air gun for providing a stream of air comprising a hollow tube having an entrance open to the atmosphere, an intermediate throat and an exit with pressurized air being directed through a small slit adjacent the throat to combine with air from the atmosphere and be ejected from the exit as a usable stream. The pressurized air is safely directed from the gun by other than the exit when the exit is closed to prevent a pressure build-up at the exit.

United States Patent [191 A Mocarski AIR GUN [75] Inventor: Zenon R. Mocarskl, Easton, Conn.

[73] Assignee: SRC Laboratories Inc., Fairfield,

Conn.

22 Filed: Mar. 14,1972

211 Appl. 190.; 234,535

[52] US. Cl 239/413, 239/417.5, 239/425.5, 239/433, 239/526 [51] Int. Cl B05b 7/12 [58] Field of Search 239/419.5, 498, 525, 239/4l7.3, 556, 288.3, 433, 434.5, 425.5, 425, 413

[56] References Cited UNITED STATES PATENTS 2,965,312 12/1968 Hale 239/433 3,129,892 4/1964 Tillman 239/417.3 3,263,934 8/1966 Hope, Jr. et a1. 239/552 [451 July 3,1973

3,599,876 8/1971 Kyburg 239/493 3,647,142 3/1972 Drude et al 239/288.3 3,419,082 12/1968 ORegan et al. 239 433 FOREIGN PATENTS OR APPLICATIONS 885,892 11/1971 Canada 239/525 Primary Examiner-Lloyd L. King Attorney-Ernest M. Junkins et a1.

[ 5 7 ABSTRACT An air gun for providing a stream of air comprising a hollow tube having an entrance open to the atmosphere, an intermediate throat and an exit with pressurized air being directed through a small slit adjacent the throat to combine with air from the atmosphere and be ejected from the exit as a usable stream. The pressurized air is safely directed from the gun by other than the exit when the exit is closed to prevent a pressure buildup at the exit.

10 Claims, 7 Drawing Figures Patented July 3, 1973 3,743,186

7 fly 33a 39 4 &6 L 545 /5 AIR GUN The present invention has especial utility in a manufacturing establishment where a stream of air is directed by an operator to perform a function, such as blowing refuse from a work station. Heretofore proposed air guns have basically consisted only of a piece of pipe having one end connected to a source of pressurized air and its other end open and through which the air is ejected with a valve controlling the quantity of air that flows. Such a construction, however, is finding increasing objection in view of safety regulations which set the maximum pressure which can appear at the exit end if it is closed. While efforts to adapt such air guns to conform to these regulations have been made, they have not been completely satisfactory as they tend to even more decrease the efficiency and effectiveness of such a gun.

It is accordingly an object of the present invention to provide an air gun for providing a working stream of air by the use of compressed air which does not permit the pressure at the exit when closed to exceed a safety maximum.

Another object of the present invention is to provide an air gun that is more efficient in forming the stream than heretofore known devices by also including ambient air in the stream in addition to the compressed air to thereby provide a stream having an effective working force.

A further object of the present invention is to obtain the above objects with an air gun that is extremely simple in construction, reliable and durable in use and economical to manufacture.

In carrying out the present invention of an air gun, there is provided a handle that includes a passageway that has one end adapted to be connected to a source of pressurized air and its other end terminate in a slit formed in a nozzle. Intermediate the passageway a manually operated valve is provided for controlling the flow of air to the slit. Particularly, the nozzle is formed to have an unobstructed bore with the pressurized air passing from the slit through the bore to be discharged at the exit end of the nozzle. In addition, the nozzle is shaped such that it utilizes the compressed air through the slit to induce the flow of ambient air through the other end or entrance of the bore so that the exited stream consists not only of the pressurized air from the slit but also ambient air. Thus the mass of the stream is greater than that of just the pressurized air which accordingly enhances the working force of the stream over just pressurized air alone.

In the event that the exit becomes closed and even with the pressurized air being on the order of I lbs/in. or so pressure, the nozzle prevents build-up of pressure at the exit, thereby effecting conformity with safety regulations. In one embodiment, the nozzle inherently reverses the direction of flow of the pressurized air through the slit when the exit is blocked and causes it to be discharged from the entrance. The user is protected from the reverse flow by a shield normally located between the entrance and the user and specifically consists of a hook portion of the handle. In another embodiment, one or more openings may communicate with the bore to permit the escape of pressurized air which tends to limit the reversal of movement of the air. Thus in both embodiments the compressed air from the slit can be safely directed away from the nozzle when the exit is closed without a pressure build-up and without interference with the normal efficiency of the nozzle. Moreover, the opening may be used normally for providing a screen of air to prevent flyback of the refuse.

Whle the present invention is primarily an air gun for providing a working stream of air, it is also contemplated that the gun may be also employed as an atomizing device if there is provided a tube for conducting the atomized fluid from the container to adjacent the slit in the bore to intermix the fluid with the discharged stream.

Other features and advantages will hereinafter appear.

In the drawing:

FIG. 1 is a side view, mostly in section, of one embodiment of the air gun of the present invention.

FIG. 2 is a partial front view, looking in the direction of the arrows 2-2 of another embodiment of the air gun of the present invention.

FIG. 3 is a view similar to FIG. 2 of another embodiment.

FIG. 4 1s a plan view of an annular spacer.

FIG. 5 is a plan view of a different annular spacer.

FIG. 6 is an enlarged detail, in cross-section, of the slit portion of the nozzle.

FIG. 7 is a cross-section of a nozzle (somewhat enlarged) showing the positioning of a tube at the slit for enabling atomization of a fluid.

Referring to the drawing, the air gun of the present invention is generally indicated by the reference numeral l0 and includes a handle 11 preferably formed of one piece of metal to include a hook 12 for supporting it. A passageway 13 is formed through the handle and includes at one end a threaded opening 14 in which an air hose connector 15 may be secured for enabling connection to a source of air under pressure. The threaded portion 14 communicates with a portion 16 of the passageway which is preferably enlarged to enable a filter to be positioned therein if desired. The passageway leads from the portion 16 to a spring-urged, normally closed valve 17 having a plunger 18 which is actuated, in the manually operated embodiment of the present invention herein disclosed, by a pivoted trigger 19. Operation of the trigger 19 opens the valve 17 to permit compressed air to pass into another portion 20 of the passageway, through a tube 21 that is secured as by set screw 22 to the handle 11 and into an annular cavity 23 formed in a nozzle 24.

The nozzle 24 includes a bore 25 of essentially constant diameter and compressed air introduced into the cavity 23 is directed through a slit 26 to pass through the bore 25 and be discharged throuh an exit 27 of the bore indicated by a dotted line. The passage of the compressed air from the slit 26 to the exit 27 induces a flow of ambient secondary air through the other open end or entrance 28 of the unobstructed bore 25 to cause the same to also pass through the bore 25 to commingle with the compressed air and also be discharged through the exit 27. The movement of the induced ambient air is indicated by arrows. Accordingly, the stream through the bore of the air gun includes not only the pressurized air which passes through the slit 26 but also includes the ambient air that is induced to flow, thereby increasing the mass of air that is capable of being discharged and enhancing the working force of the stream.

The stream of air through the exit may be discharged directly or, as shown, be subdivided mostly into a main stream with the remainder being discharged obliquely thereto to form an air shield to minimize flyback of refuse. Thus in FIG. 1 there is a reduced diameter tube portion 29 having an open discharge end 30* through which the main stream is discharged. For the flyback screen, a transverse arcuate slot 31 communicates with the bore just prior to the reduced tube portion 29. Thus air through the exit 27 is caused to be subdivided by the reduced tube portion 29 into a main stream that is ejected from the end 30 and a flyback screen that is ejected from the slot 31.

If desired, as shown in FIG. 3, the slot 31 may be replaced by a plurality of arcuately disposed holes 32 that also transversely communicate with the bore adjacent the exit 27.

In the event that open end 30 becomes closed while the valve 17 is open, the present invention provides for directing the compressed air that flows through the slit 26 away from the nozzle and the operator. In the embodiment shown in FIG. 1, closure of the open end 30 still permits air to be discharged through the slot 31. If all the air cannot pass through the slot 31, a slight (on the order of only a few pounds per square inch) pressure build-up occurs in the bore which will cause air to be discharged through the entrance 28 of the nozzle. The operator is protected from this reverse flow by the book 12 having the shape shown and at the back of the gun to be positioned in the path of the air discharging through the entrance 30 to form a shield. Thus any re verse air stream will impinge upon the handle 11 and be dispersed. In the above-described embodiment of the invention even though the air valve 17 is open admitting air under high pressure, closure of the open end 30 does not permit a pressure build-up thereat and the compressed air is caused to safely flow from the air gun in a manner which will not be detrimental to the user.

The nozzle 24 shown in FIG. 1 consists of an exit part 33 that is cylindrical having the cross-sectional shape shown and in which the annular cavity 23 is formed, and an entrance part 34 that is also cylindrical having the cross-sectional shape shown. The entrance part 34 is fitted within an annular groove 35 formed in the adjacent end of the exit part 33 with an annular spacer 36 positoned therebetween in order to form the slit 26. The part 34 may be mechanically or otherwise secured to the part 33 in any convenient manner, one manner being by staking.

If desired, rather than have a completely annular slit 26, the slit may be formed into small segments by the use of the spacer shown in FIG. and indicated by the reference numeral 37 which causes the slit 26 to be interrupted into a plurality of segments. It will be understood that the thickness of the spacer 36 (or 37) determines the thickness of the slit 26, an one thickness of the spacers that has been found satisfactory is 0.003 inches. Also, if desired, the size of theslit which sets the maximum quantity of flow of compressed air may be decreased by the use of a spacer shown in FIG. 5 so that the slit size may be controlled by either or both of the thickness of the spacer and/or by segmenting the slit.

Referring to FIG. 6, the slit 26 is formed between a flat surface 33a of the exit part 33 and another flat surface 34a of the entrance part 34. Another surface 33b curves inwardly into the bore and towards the exit 27 to a throat 38 of the bore. The throat has the smallest cross-sectional area of the bore that is closest to the entrance 30 and preferably the bore maintains the same size as the throat to the exit 27 in order to minimize turbulence and dispersion of the stream. The surface 34a terminates at 34b in a diameter that is larger than the throat 38 and just slightly toward the axis of the bore where the flat surface 33a terminates. It will also be understood that the outer surface 340 that forms the entrance 28 is made as an extremely flat curve as shown.

Accordingly, the compressed air passing through the slit 26 tends to follow the curved surface 33b to the throat 38 and in doing so induces the flow of air indicated by the arrows. For a more full description of the operation of the slit and nozzle, reference is made to my copending application Ser. No. 153,172, filed June 15, l97l and entitled Fluid Volume Amplifier.

Though the present invention is primarily designed for use as an air gun, it has also been found that if a tube, such as a tube 39 in FIG. 7, is connected to a container of material such as water, light oil, or even abrasive material such as sand, that the nozzle will create a vacuum in the tube 39 that will draw the material into the tube, atomize it in the bore 25 and discharge it with the stream from the exit 27 with the material being dispersed and commingled in the stream. It has been found that the end of the tube 39a should be positioned no further into the tube than the throat 38, and no further withdrawn from the tube than just slightly behind the slit 26. Preferably, as shown, it is located just adjacent the throat 38 but slightly spaced therefrom towards the entrance 28. Also the size of the tube should be substantially less than the throat and diameter of surface 34b in order not to interfere with the induced flow.

It is preferably desired when using the gun for atomization to eliminate the subdividing of the stream and have the bore extend at the same size throughout the length of the nozzle, as shown in FIG. 7, wherein the exit 27 constitutes the discharge opening. This structure of the nozzle may also be found useful, when subdividing to form a flyback prevention screen is not desired, in order to increase the working force of the main discharge stream.

It will accordingly be appreciated that there has been disclosed an air gun which is capable of providing a stream of discharged air which has a relatively large mass since the stream includes not only compressed air but also an induced flow of secondary air. Moreover, closure of the exit of the gun even with the flow of compressed air being maintained into the nozzle does not effect a build-up of pressure at the exit so as to exceed safety regulations limiting the maximum pressure which can exist at a closed exit. Though the air escapes from the nozzle, the user is protected therefrom by both or either a shield located at the entrance of the bore and/or by the ejected stream being directed transversely of the bore by the use of an opening which communicates with the bore.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. An air gun for forming a stream of air comprising a handle, conduit means carried by the handle and including a connection at one end adapted to be connected to a. source of compressed air, a nozzle sup ported on the handle and formed to have a bore with one end being open to form an entrance and the other end being open to form an exit whereby air may pass uninterrupted through the bore, said bore also being formed with a restricted area throat adjacent the entrance, a slit formed in the nozzle and communicating with the bore between the throat and the entrance, means connecting the other end of the conduit means to the slit, and valve means connected to the conduit means for controlling the passage of compressed air through the conduit means and slit into the bore.

2. The invention as defined in claim 1 in which there are means for dispersing the air passing through the bore upon closure of the exit.

3. The invention as defined in claim 2 in which the dispersing means includes a shield positioned adjacent the entrance for dispersing the flow of air through the entrance and consisting of a surface on a portion of the handle.

4. The invention as defined in claim 2 in which the dispersing means includes at least one opening communicating transversely with the bore adjacent the exit.

5. The invention as defined'in claim 1 in which the nozzle includes at least two parts and the slit is disposed about the bore and located between adjacent surfaces of the parts.

6. The inventionas defined in claim 5 in which the slit is formed to be annular.

7. The invention as defined in claim 5 in which the slit is formed by a plurality of individual, spaced-apart segments.

8. The invention as defined in claim 5 in which there is a spacer located between the two parts at their adjacent portions and in which the thickness of the spacer sets the width of the slit.

9. The invention as defined in claim 1 in which the throat has the narrowest cross-sectional area of the bore nearest the entrance, the slit is formed between a transverse surface that terminates in a cross-sectional area greater than the throats cross-sectional area, a curved surface that curves crosswise to lengthwise of the bore along the length of the bore from the entrance towards the exit with the curved surface being located nearer the throat than the transverse surface.

10. The invention as defined in claim 1 in which there is a reducing tube connected to the exit and having a smaller cross-section than the exit and in which there is a transverse opening communicating with the bore adjacent the exit whereby the stream from the exit may be subdivided. 

1. An air gun for forming a stream of air comprising a handle, conduit means carried by the handle and including a connection at one end adapted to be connected to a source of compressed air, a nozzle supported on the handle and formed to have a bore with one end being open to form an entrance and the other end being open to form an exit whereby air may pass uninterrupted through the bore, said bore also being formed with a restricted area throat adjacent the entrance, a slit formed in the nozzle and communicating with the bore between the throat and the entrance, means connecting the other end of the conduit means to the slit, and valve means connected to the conduit means for controlling the passage of compressed air through the conduit means and slit into the bore.
 2. The invention as defined in claim 1 in which there are means for dispersing the air passing through the bore upon closure of the exit.
 3. The invention as defined in claim 2 in which the dispersing means includes a shield positioned adjacent the entrance for dispersing the flow of air through the entrance and consisting of a surface on a portion of the handle.
 4. The invention as defined in claim 2 in which the dispersing means includes at least one opening communicating transversely with the bore adjacent the exit.
 5. The invention as defined in claim 1 in which thE nozzle includes at least two parts and the slit is disposed about the bore and located between adjacent surfaces of the parts.
 6. The invention as defined in claim 5 in which the slit is formed to be annular.
 7. The invention as defined in claim 5 in which the slit is formed by a plurality of individual, spaced-apart segments.
 8. The invention as defined in claim 5 in which there is a spacer located between the two parts at their adjacent portions and in which the thickness of the spacer sets the width of the slit.
 9. The invention as defined in claim 1 in which the throat has the narrowest cross-sectional area of the bore nearest the entrance, the slit is formed between a transverse surface that terminates in a cross-sectional area greater than the throat''s cross-sectional area, a curved surface that curves crosswise to lengthwise of the bore along the length of the bore from the entrance towards the exit with the curved surface being located nearer the throat than the transverse surface.
 10. The invention as defined in claim 1 in which there is a reducing tube connected to the exit and having a smaller cross-section than the exit and in which there is a transverse opening communicating with the bore adjacent the exit whereby the stream from the exit may be subdivided. 